1. Field of the Invention
The invention in general relates to inductors, and more particularly to a superconducting inductor for energy storage.
2. Description of Related Art
An electrical inductor is capable of storing energy in the magnetic field produced by current flowing through the inductor. If the inductor is a superconducting inductor, extremely large amounts of energy can be stored for relatively long periods of time in that once in the superconducting state, resistance of the inductor winding approaches zero ohms enabling the winding to carry large currents with little loss. A cryogenic fluid system keeps the inductor at the temperature required for superconductor operation.
Superconducting magnetic energy storage systems find use in the electrical utility industry and may be used in industrial, transportation and defense applications. A commonly used superconducting inductor takes the form of a cylindrical solenoid which allows more energy to be stored within a given volume. These solenoidal superconducting inductors produce an extremely large external magnetic field that not only may impair other electrical equipment, but poses a health risk to personnel in the vicinity.
Toroidal inductors which produce relatively smaller external magnetic fields have also been constructed. However, for the same amount of energy the toroidal inductors require more turns and larger coils.
The solenoidal superconducting inductors require extensive magnetic shielding such as thick steel plates, to reduce the exclusionary zones for equipment and personnel.
The inductor of the present invention significantly decreases the exclusionary zone volume and without the requirement for extensive magnetic shielding.